Question

I’d like to fill a char-array dynamically and check whether the contained values are valid integers, here’s what I got so far:

for(int i = 0; i < 50000; i++)
    {
        if(input[i] == ',')
        {
            commaIndex = i;
        }
    }

commaIndex is the index of a comma inside a file, numerical values should have been entered before a comma, file looks like this: -44,5,19,-3,13,(etc), it’s important for this part:

char *tempNumber = new char[commaIndex];

Fill tempNumber (which should presumably be just as big as the number due to my dynamic allocation) so I don’t have a number in a size 50000 char-array (named input).

for(int i = 0; i < commaIndex; i++)
    {
            cout << i << "\n";
            tempNumber[i] = input[i];
    }

And now I want to use it:

if(!isValidInteger(tempNumber))
    {
        cout << "ERROR!\n";
    }

Unfortunately, tempNumber always seems to be of size 4 irregardless of the value of “commaIndex”, i.e. I get the following output:

(Inputdata: 50000,3,-4)

commaIndex: 5
content of tempNumber: 5000 (one 0 missing)

commaIndex: 1
content of tempNumber: 3²²² (notice the 3 ^2s)

commaIndex: 2
content of tempNumber: -4²²

Any ideas?

One more thing: This is for a homework assignment and I am not allowed to use any object-oriented element of C++ (this includes strings and vectors, I’ve been there and I know it would be SO easy.)

Thanks,

Dennis

Answer 1

You might be interested by the strtol function.